Liquid-hammer icebreaker for ships

ABSTRACT

Open water ice breaking means and method including in one embodiment a vertical tube for disposal beneath floating ice, valves for closing off the ends of the tube, a pump for evacuating ambient water from the tube, and a control system for admitting water to gush upward under ambient pressure through the lower valve, the evacuated tube and the upper tube, to break the ice through impact of the upward moving column of water against the lower face of the ice; in a second embodiment a plurality of tubes similar to that described operates in synchronism to focus the effect produced by impact of the water on the ice; alternating operation of a plurality of tubes is provided in another, similar embodiment; a further embodiment uses compressed air to displace the ambient fluid and operates without top and bottom valves; special tubes and valves are provided for the invention, as well as ship adaptions.

United States Patent 11 1 [111 Wagner Jan. 15, 1974 LIQUID-HAMMER ICEBREAKER F OR Primary ExaminerGeorge E. A. Halvosa SHIPS Assistant ExaminerGregory W. OConnor [76] Inventor: Jacob W. Wagner, Schuster Rd., Attorney-John McClellan J arrettsville, Md.

[57] ABSTRACT [22] Flled' June 1972 Open water ice breaking means and method including [21] Appl. No.: 263,554 in one embodiment a vertical tube for disposal be- Related Us. Appfication Data neath floating ice, valves for closing off the ends of the tube, a pump for evacuating ambient water from the [63] cohtthuatich'th'patt of q f tube, and a control system for admitting water to gush tygf l g 'fi g i M213 upward under ambient pressure through the lower valve, the evacuated tube and the upper tube, to break the ice through lmpact of the upward movmg column 52 us. c1. 114/40 watt against the tact of the a Second 51 int. c1 B63b 35/08 embodiment a pthtahty of tubes Stthhat that [58] Field of Search 114/40 41 42 scribed Petatts syhchtthtsm focus the effect produced by impact of the water on the ice; alternat- [561 References Cited 1 ing operation of a plurality of tubes is provided in another, similar embodiment; a further embodiment uses UNITED STATES PATENTS compressed air to displace the ambient fluid and oper- Wagner ates without top and bottom alves; pecial tubes and 31698340 10/1972 Wagner 114/40 valves are provided for the invention, as well as ship 3,130,701 4/1964 Langballe ll4/4O ada tions 3,572,273 3/1971 Wood 114/40 p I 28 Claims, 19 Drawing Figures rrTf V .340 l 342 342 A 41/300 300 M *300 312 A J 1 3l2 /3|2 t t 328 T 1 32a 1 338 P i K 338 P -1 PATENTEBJAH 15 1974 SHEET 2 [IF 4 652 Him FIG. 7

FIG.8

PATENTEDJAMSW 3.785.315

sum 3 [IF 4 0 0 U MO FIG-9 FIG. IO FIG. II

FIG.I2

PATENTEDJM! 15 ISM SHEET Q 0? 4 FIG. l3

LIQUID-HAMMER ICEBREAKER FOR SHIPS This invention is a continuation in part of my prior filed co-pending U.S. Pat. application, Ser. No. 16,516, filed Mar. 4, 1970, for Ice Breaking Hammer Attachment For Ships, issued as U.S. Pat. No. 3,698,341, and U.S. Pat. Ser. No. 120,271 filed Mar. 2, 1971, for ICE BREAKING SYSTEM FOR SHIPS issued as U.S. Pat. No. 3,698,340.

This invention relates generally to shipping and particularly to ice breaking apparatus for opening channels through floating ice including pack ice.

The economic importance of opening a practicable sea route for oil transport from the Alaska north shore area can scarcely be overestimated in view of the quantities of oil available, and the difficulties, expense, and environmental hazards inherent in overland transport of the oil.

Many different icebreakers have been disclosed in the prior art, including those of my above referenced co-pending disclosure which are advantageously adapted for particular ice breaking problems.

It is, however, a principal object of the present invention to provide even more advantageous means and method for ice breaking than those previously disclosed. Special advantages and objects of the present invention include provision of an icebreaking system which:

is adapted to break the heaviest pack ice quickly, economically and reliably,

employs a moving mass of water accelerated over a long path by non-polluting means to' impact and break the ice;

creates a minimum of disturbance of marine life and habitat as result of the ice breaking operation;

employs a minimum of parts operating under low stress and without requirement for high precision construction;

can be employed singly or in groups, can in groups be synchronized to focus the percussive effect on the ice, to produce whipsaw like phase related alternating percussions, and to produce flotation-stabilizing out-ofphase percussions;

can be operated by means of compressed air displacement of liquid in an open-ended constraint struc ture in one embodiment and by means of liquid pump evacuation of a valve-closed constraint structure in another embodiment;

and which has in various embodiments special valving, valve protective, self propelling, and depth adjustment provisions.

In brief, exemplary summary the invention comprises means and method for creating a shaped liquid-void below ice to be broken and in constraining liquid return in' filling the 'void to form a high momentum column of returning liquid which inelastically impacts on the underside of the ice.

The above and other advantages and objects of the invention will be more readily understood from the following description, including the drawings in which:

FIGS. la, lb, and 1d are side elevations of an embodiment of the invention;

FIG. 2 is a side elevation of a modified version of the FIG. I embodiment;

FIGS. 3a, 3b and 3c are side elevations, partly in section, of another embodiment of the invention;

FIG. 4 is a plan of the top of an embodiment of the invention;

FIG. 5 is an idealized section of the FIG. 4 embodiment;

FIGS. 6 and 7 are side elevation details of further embodiments;

FIG. 8 is a side elevation detail of yet a further embodiment;

FIGS. 9, l0 and 11 detail in perspective three positions of operation of an alternative valve designed for operation as part of this invention;

FIG. 12 is a bottom perspective detail of the invention; and

FIGS. 13 and 14 are plan and elevation of an embodiment.

In the drawings similar parts are similarly numbered.

Taking up FIG. 1 in 'detail, the embodiment comprises simply a vertical tube 12 open at each end, means for supporting the tube 12 beneath an ice floe I tobe broken, such as by a pivotal hollow link 14 to a ship 16, means to supply a large quantity of compressed gas to the tube in a short time, as through a pump 18, storage tank 20, valve 22, conduit 24 and port 26 from ship to tube 12, and a synchronizing control system 28.

In operation, beginning with the tube 12 filled with ambient water, as in FIG. la, compressed air is suddenly admitted to the system to the extent necessary to expel substantially all water from the tube 12 as in FIG. 1b; the compressed air is shut off allowing water to surge upward through the tube, driving the air out ahead of it as in FIG. 1c; and the momentum of the water causes it to impact against the ice with shattering effect as in FIG. 1d.

The valve control device 28 may be of any conventional type, such as a solenoid actuator which senses and triggers on pressure changes in the fluid system below the valve 22. The valve 22 may be aboard ship as shown or at any convenient location from that point down to the tube.

FIG. 2 shows an alternate embodiment 200 of the FIG. 1 invention, which employs a plurality of tubes 212 in parallel array. The tubes may have individual valves 222 and controls 228, preferably near the ports 226, and be actuated simultaneously, or may be actuated in alternation of single units or groups to set up a resonant hammering of water columns on the ice. Supply line 224-258 feeds the peripheral tubes and supply line 260 which may extend downwardly from and feed an interior sealed tube 262 at the bottom. Tube 262 in turn acts as a manifold to supply other interior tubes as through port 264.

FIG. 3 shows in partial section at 3a, 3b and 3c the construction and ice breaking action of a further embodiment 300. Vertical tube 312 has a top valve 330, a bottom valve 332a, bottom valve actuator 334, an exhaust port 326 at one side of the bottom portion of the tube, a high speed liquid evacuating pump 338 connected to the exhaust port, an energy supply line 340 for the pump and valve synchronizing control 328, a pump exhaust duct 342, and means such as hydraulic ram arms or such, such as chains 314 for controlling the position of the device.

The top valve 330 is preferably of a special articulated plural-facet construction which is upwardly pyramidal in shape when viewed from above in the closed position. The facets 344 of the valve are triangular, with the base of each triangular facet hinged to the tube 312. When open, the valve facets form a serrated collar inside the tube, preferably, as shown, spaced down from the upper end of the tube enough to prevent damage to the valve through contact with ice. Preferably the facets are edged with sealing rubber strips, and bear relatively weak springs 346 for closure.

This design allows the top valve to pop open under excess of lower pressure over upper pressure at the valve, with low-inertia operation in a high-strength design.

The bottom valve 332 is preferably a quick opening poppet valve, or a quick opening slide valve such as that shown. Actuator 334 includes a motor driven rotating part which engages the top surface of the valve and slides it open and shut on ways 348. The top valve may also be of this design, but if so, will require careful synchronization in operation. Alternatively, the top valve can be accordian pleated in a preferably onepiece design as discussed later in reference to FIGS. 9-11.

Synchronizing control 328 senses presence of liquid in the pump intake, and shuts off the pump and opens the bottom valve when liquid has been evacuated from the tube. If the top valve is a slide valve, the controller may be timed to open the top valve a fixed interval after the botom valve opens, just before the upward gush of water reaches the top valve.

In operation, both valves 330 and 332 are closed and the tube 312 is exhausted through port 326, pump 338 and exhaust duct 342. The exhaust duct preferably exhausts horizontally beneath the water toward the ship (not shown) which controls and supplies power to the device. The reaction of the exhaust drives the device under the ice ahead of the ship, and if positioned below the constraints 314 to the ship, tends to keep the device vertical while moving. Horizontal exhaust below the water partway up the length of the device also prevents undue disturbance of the bottom of the sea or other body of water by operation of the device. With the tube 312 evacuated as in FIG. 3a, bottom valve 332 is then opened and a column of ambient water gushes up through the tube as in FIG. 3b, knocks open the top valve 330, and smashes into the ice above as in FIG. 3c. The cycle is then repeated automatically.

Flotation tanks, like that at 350, FIG. 3, which is a large tank on the far side and which may be paired with a similar tank on the near side, may be welded or otherwise affixed to any of the embodiments.

FIG. 4 shows a top view of a plurality of hexagonal pyramidal valves 430 similar to that of FIG. 3, mounted on six nested hexagonal tubes 412. Three ducted exhaust pumps 438, each serving two tubes, are shown, as well as three flotation chambers 450. The interbuttressed compactness, strength, and economy of this honeycomb arrangement can easily be seen.

FIG. 5, an idealized section through 5-5 of the FIG. 4 embodiment shows the focussing effect obtained by the nesting arrangement of FIG. 4. The column of water emerging from the central tube is constrained to continue in the upward direction by the pressures generated by the columns emerging from peripheral tubes. There are no interstices between the tubes to vent the pressures downward, and the impact forces are more effectively concentrated.

FIG. 6 shows a tube 612 having three sections 652, 654 and 656 which telescope for adjustment of depth and hence effectiveness, clearance and storage, the end tube sections 652 and 656 in this embodiment fitting into the middle tube section 654 and being retained by clamps 658.

FIG. 7 shows a tube 712 having a flexible lower portion 756 which prevents damaging from shoaling.

FIG. 8 is a side elevation of an embodiment 800 of the invention, adapted to be clamped as by retainer 892 in the extended ram 894 of a specially adapted ship 816. This arrangement keeps the unit 800 vertical at all times and protects it from ice damage. Operation can either be by compressed air or by valve-and-pump as previously described. The unit may be lifted free and stored on deck by winching it straight upwards, when it is not required for icebreaking.

As previously noted, the top valve of this invention can be accordian-pleated of rubber, plastic, or other suitable material as shown in FIGS. 9, 10 and 11, preferably in one piece.

FIG. 9 shows this valve embodiment 930 fully closed, FIG. 10 shows it partially open and FIG. 11 shows it fully open. The valves can have almost any number of flutes 992, but a relatively few (five shown) will serve.

Installation is preferably in the position indicated in FIG. 9 relative to the tube 912 shown in phantom lines. The valve may be cemented in place, or bolted as at 972, or both, along the lower periphery 974; the periphery may be band reinforced and may have a feather edge, fairing it to the tube 912.

The top may have an internal spring 976 to force it shut, and may have paired magnets 978, 980 on opposed sides of each fold to keep it shut. A magnet 982, shown in phantom lines, may be provided on the wall of the tube at a position and in an orientation to repel each one of the magnets on the valve proper, to assist the valve in closing from the fully open position Operation is similar to that of the valve described in reference to FIG. 3, but the present valve has no vented triangular areas in the sides when opening, and consequently is snapped open to the fully cylindrical position under a different mechanical advantage by the upsurge of the water. The sealing portions in the present valve are substantially in-plane, and inter-linked, in contrast with the FIG. 3 arrangement, so that the sealing mode is different from that of the FIG. 3 embodiment. Also, the present valve is somewhat better adapted for installation in circular tubes than the FIG. 3 valve, although with six flutes it is ideally adapted for installation in nested tubes such as those of FIG. 12 and can be embodied in any regular polyhedral section tube.

FIG. 12 is a detail of an embodiment 1200 which has flotation chamber 1250 surrounded by a plurality of tubes 1230. The tubes have coarse mesh 1283 or other sieve material over the ends to prevent entry of solid matter, including ice fragments and larger forms of sea life. A remote indicating water sensor 1285 may be affixed in a lower part of the tubes of any embodiment to monitor performance of the system valves and synchronization.

FIGS. 13 and 14 detail ship adaptions according to this invention in plan and elevation respectively, foreshortened by sectioning amidships.

In this embodiment 1300 a special ship 1316 is provided with a downwardly inclined ram bow 1394, designed to lift ice (FIG. 14) and honeycombed vertically with a plurality of fitted tubes 1312.

The tubes may be of the type described in relation to FIG. 1, but are preferably, as illustrated, the FIG. 3 type. Pumping ducts 1342 are spaced beneath the lower end of the tubes 1312, and preferably are arranged to exhaust six-tube clusters through surrounded manifold tubes 1362 nested within them which have radiating ports 1364 to them. Highspe'ed shipboard pumps (not shown) are connected with the exhaust ducts. Optionally the FIG. 3 arrangement can be used, with reduction in total number of tubes which can be nested in the prow.

Poppet type valves 1332 (FIG. 14) ganged on common axles 1398 and having actuating lever arms 1399 at the ends, in turn actuated from shipboard by rods 1397, can be used to seal the lower ends of the tubes. The upper ends of the tubes are sealed preferably by valves 1330 such as those of FIGS. 3 or 9. Operation is generally as described with reference to FIGS. 3 and 4. Port and starboard tubes can be alternated in operation to roll the ship or in synchronism to cause a pitching motion, helping root-under and snap ice as well as breaking the ice by tube ejections as previously described.

Cooperating with the prow tubes to roll and pitch the ship can be arrays of open bottom ballast tanks 1350, 1351, in the bow and stem respectively of the ship and supplied by pneumatic lines 1324, 1325 from a shipboard source, not shown. These can also be supplied in clusters. Synchronism can be by an ordinary gravitysensitive detector system which controls valves in, or out, of phase as required to achieve the desired pitch or roll.

The ship 1316 preferably is wider in the prow 1394 and bow 1395, as indicated, than in the after portions, to free the sides from ice pressure when breaking ice by forward motion.

lt will be apparent from the foregoing that thrust tubes and variable ballasttanks of the types described can be interspersed throughout the prow if desired, to emphasize one type action over the other. Further, it will be apparent that the combination of imposing a bending load on ice by lifting it with the prow and then applying the liquid hammer to the stressed portion will be particularly effective in breaking the ice.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed and desired to be secured by United States Letters Patent:

1. A system for breaking ice floating on water comprising: means for constraining fluid in a vertically elongated space proximate the lower face of floating ice to be broken, means for substantially exhausting ambient liquid from the means for constraining fluid, means for causing ambient liquid impelled by ambient pressure to gush upwardly through the means for constraining fluid to impact upon the lower face of floating ice to be broken, thereby breaking said ice.

2. A system for breaking ice floating on water, as recited in claim 1, wherein the means for constraining ambient fluid comprises at least one tube, a valve adjacent the top of the tube, a valve adjacent the bottom of the tube, a liquid exhaust pump connected with the ,tube interior, and means for controlling the valves and exhaust pump whereby in cycle the tube is first exhausted of ambient water and ambient water is then admitted through the bottom valve and permitted to gush through the top valve.

3. A system for breaking ice floating on water, as recited in claim 2, and means adapting the top valve to open upon application of pressure beneath the top valve in excess of pressure above the top valve.

4. A system for breaking ice floating on water, as recited in claim 2, wherein the top valve is positioned lower than the uppermost part of the tube structure.

5. A system for breaking ice floating on water, as recited in claim 3, where in the tube is polygonal in shape.

6. A system for breaking ice floating on water, as recited in claim 5, wherein the top valve is upwardly pyramidal in shape, with the base of each face of the pyramid hinged at a corresponding face of the polygonal tube.

7. A system for breaking ice floating on water, as recited in claim 3 wherein the top valve is upwardly pyramidal in shape.

8. A system for breaking ice floating on water, as recited in claim 2 wherein the liquid exhaust pump connection is to a lower portion of the tube.

9. A system for breaking ice floating on water, as recited in claim 2, wherein the liquid exhaust pump is connected to the tube and wherein the liquid exhaust is directed substantially horizontally.

10. A system for breaking ice floating on water, as recited in claim 2, wherein the bottom valve is a poppet type valve.

11. A system for breaking ice floating on water, as recited in claim 2 wherein a lower portion of the length of the tube is disposed at an angle to the upper portion of the tube.

12. A system for breaking ice floating on water, as recited in claim 2 and means for connecting the tube with a ship.

13. A system for breaking ice floating on water, as re cited in claim 2 wherein a portion of the tube is flexible.

14. A system for breaking ice floating on water, as recited in claim 2, wherein the means for constraining ambient fluid comprises a plurality of tubes and wherein the upper ends of the tubes are juxtaposed, with at least one of the tubes surrounded by the other tubes.

15. A system for breaking ice floating on water, as recited in claim 14, wherein the means for controlling is connected to control a plurality of the tubes.

16. A system for breaking ice floating on water, as recited in claim 2, wherein at least one flotation chamber is connected with said at least one tube.

17. A system for breaking ice floating on water, as recited in claim 2, wherein the means for causing the ambient liquid to gush upwardly includes a plurality of tubes, a tubular manifold within the interior of said plurality of tubes, said tubular'manifold having at least one opening communicating with an adjacent tube, and a fluid-conducting conduit connected with said tubular manifold.

18. A system for breaking ice floating on water as recited in claim 1, and in combination therewith a ship, the ship having a downwardly inclined ram blow adapted for lifting ice, a plurality of said means for constraining fluid vertically disposed through said downwardly inclined ram bow.

19. A system for breaking ice as recited in claim 2, said means for constraining fluid comprising nested polyhedral-section tubes.

20. A system for breaking ice as recited in claim 19, wherein ganged valves are provided for sealing the lower ends of the tubes.

21. A system for breaking ice as recited in claim 20, wherein manifold tubes having pumping ducts are connected with plural of said tubes, thereby providing for said tubes to be operated in clusters.

22. A system for breaking ice as recited in claim 18, and additionally, a plurality of open-bottom ballast tubes disposed through forward and aft portions of the hull of said ship.

23. A system for breaking ice as recited in claim 22, and ballast manifold tubes having pumping ducts connected with plural of said open bottom ballast tubes, thereby providing for said open bottom ballast tubes to be operated in clusters.

24. A system for breaking ice as recited in claim 1, wherin the means for constraining fluid comprises a plurality of polyhedral-section tubes, said plurality of polyhedral-section tubes being nested together in honeycomb relation.

25. The method of breaking ice floating on water, consisting of the steps:

a. creating a liquid-void in a constrained vertically extended space adjacently beneath floating ice;

and

b. causing ambient liquid to gush upward through the liquid void in the constrained vertically extended space to inelastic impact upon the lower face of the floating ice, thereby breaking the ice.

26. The method of claim 25 and additionally the step (c) stabilizing the ice breaking operation by:

i. creating, out of phase with step (a), a second liquid void in a constrained vertically extended space proximate the first said liquid void; and

ii. causing, out of phase with step (b), ambient liquid to gush upward through the second said liquid-void in the constrained vertically extended space to inelastic impact upon the lower face of the floating 27. The method of claim 26, wherein the ambient liquid is caused to gush upward by the additional step of venting the bottom of the void to ambient liquid.

28. The method of claim 25, wherein after step (b) is added the following step:

c. stressing the floating ice in the area to be broken by lifting a portion thereof concurrently with step (b) above. 

1. A system for breaking ice floating on water comprising: means for constraining fluid in a vertically elongated space proximate the lower face of floating ice to be broken, means for substantially exhausting ambient liquid from the means for constraining fluid, means for causing ambient liquid impelled by ambient pressure to gush upwardly through the means for constraining fluid to impact upon the lower face of floating ice to be broken, thereby breaking said ice.
 2. A system for breaking ice floating on water, as recited in claim 1, wherein the means for constraining ambient fluid comprises at least one tube, a valve adjacent the top of the tube, a valve adjacent the bottom of the tube, a liquid exhaust pump connected with the tube interior, and means for controlling the valves and exhaust pump whereby in cycle the tube is first exhausted of ambient water and ambient water is then admitted through the bottom valve and permitted to gush through the top valve.
 3. A system for breaking ice floating on water, as recited in claim 2, and means adapting the top valve to open upon application of pressure beneath the top valve in excess of pressure above the top valve.
 4. A system for breaking ice floating on water, as recited in claim 2, wherein the top valve is positioned lower than the uppermost part of the tube structure.
 5. A system for breaking ice floating on water, as recited in claim 3, where in the tube is polygonal in shape.
 6. A system for breaking ice floating on water, as recited in claim 5, wherein the top valve is upwardly pyramidal in shape, with the base of each face of the pyramid hinged at a corresponding face of the polygonal tube.
 7. A system for breaking ice floating on water, as recited in claim 3 wherein the top valve is upwardly pyramidal in shape.
 8. A system for breaking ice floating on water, as recited in claim 2 wherein the liquid exhaust pump connection is to a lower portion of the tube.
 9. A system for breaking ice floating on water, as recited in claim 2, wherein the liquid exhaust pump is connected to the tube and wherein the liquid exhaust is directed substantially horizontally.
 10. A system for breaking ice floating on water, as recited in claim 2, wherein the bottom valve is a poppet type valve.
 11. A system for breaking ice floating on water, as recited in claim 2 wherein a lower portion of the length of the tube is disposed at an angle to the upper portion of the tube.
 12. A system for breaking ice floating on water, as recited in claim 2 and means for connecting the tube with a ship.
 13. A system for breaking ice floating on water, as recited in claim 2 wherein a portion of the tube is flexible.
 14. A system for breaking ice floating on water, as recited in claim 2, wherein the means for consTraining ambient fluid comprises a plurality of tubes and wherein the upper ends of the tubes are juxtaposed, with at least one of the tubes surrounded by the other tubes.
 15. A system for breaking ice floating on water, as recited in claim 14, wherein the means for controlling is connected to control a plurality of the tubes.
 16. A system for breaking ice floating on water, as recited in claim 2, wherein at least one flotation chamber is connected with said at least one tube.
 17. A system for breaking ice floating on water, as recited in claim 2, wherein the means for causing the ambient liquid to gush upwardly includes a plurality of tubes, a tubular manifold within the interior of said plurality of tubes, said tubular manifold having at least one opening communicating with an adjacent tube, and a fluid-conducting conduit connected with said tubular manifold.
 18. A system for breaking ice floating on water as recited in claim 1, and in combination therewith a ship, the ship having a downwardly inclined ram blow adapted for lifting ice, a plurality of said means for constraining fluid vertically disposed through said downwardly inclined ram bow.
 19. A system for breaking ice as recited in claim 2, said means for constraining fluid comprising nested polyhedral-section tubes.
 20. A system for breaking ice as recited in claim 19, wherein ganged valves are provided for sealing the lower ends of the tubes.
 21. A system for breaking ice as recited in claim 20, wherein manifold tubes having pumping ducts are connected with plural of said tubes, thereby providing for said tubes to be operated in clusters.
 22. A system for breaking ice as recited in claim 18, and additionally, a plurality of open-bottom ballast tubes disposed through forward and aft portions of the hull of said ship.
 23. A system for breaking ice as recited in claim 22, and ballast manifold tubes having pumping ducts connected with plural of said open bottom ballast tubes, thereby providing for said open bottom ballast tubes to be operated in clusters.
 24. A system for breaking ice as recited in claim 1, wherin the means for constraining fluid comprises a plurality of polyhedral-section tubes, said plurality of polyhedral-section tubes being nested together in honeycomb relation.
 25. The method of breaking ice floating on water, consisting of the steps: a. creating a liquid-void in a constrained vertically extended space adjacently beneath floating ice; and b. causing ambient liquid to gush upward through the liquid void in the constrained vertically extended space to inelastic impact upon the lower face of the floating ice, thereby breaking the ice.
 26. The method of claim 25 and additionally the step (c) stabilizing the ice breaking operation by: i. creating, out of phase with step (a), a second liquid void in a constrained vertically extended space proximate the first said liquid void; and ii. causing, out of phase with step (b), ambient liquid to gush upward through the second said liquid-void in the constrained vertically extended space to inelastic impact upon the lower face of the floating ice.
 27. The method of claim 26, wherein the ambient liquid is caused to gush upward by the additional step of venting the bottom of the void to ambient liquid.
 28. The method of claim 25, wherein after step (b) is added the following step: c. stressing the floating ice in the area to be broken by lifting a portion thereof concurrently with step (b) above. 